Drafting machine



March 23, 1948. KETTING 2,438,220

DRAFTING MACHINE Filed Oct. 2, 1943 3 Sheets-Sheet 1 March 23, 1948. L.KETTING DRAFTINQ MACHINE 5 Sheets-Sheet Filed Oct. 2, 1.945

INVENTQR LEENDERT KETT/NG ATTORNEY 5 Mafch 23, 1948. 1... KETTINGDRAFTING MACHINE 3 Sheets-Sheet 3 Filed Oct. 2, 1943 INVENTOR LEENDERTKETT/NE ATTO R N EYS Patented Mar. 23., 1948 DRAFTIN G MACHINE LeendertKetting, Secaucus, N. J., assignor to Keuffel & Esser Company, Hoboken,N. J., a corporation of New Jersey Application October 2, 1943, SerialNo. 504,668

This invention relates generally to parallel motion drafting devices ofthe kind in which the several tools which the draftsman handles mostfrequently are embodied, in principle, in one unit to obviate thenecessity of a draftsman reaching about for a required tool and therebyenabling the draftsman to keep his attention concentrated directly uponthe drawing. More particularly the invention relates to parallel motiondrafting devices of the band and pulley type although not so limited.

Drafting devices of this character are common in which an arm, broadlyspeaking, is articulated and whereof adjacent ends of two arm sectionsare pivoted together, the free end of one arm section being secured tothe remote side of a drafting board while the free end of the other armsection is provided with a head comprising a protractor andstraight-edges which are in fixed angular relation to move about thecenter of the protractor as an axis. Where a drafting device of thischaracter is used upon a drawing board which is disposed in an inclinedplane, the weight of the free arm and/or the head on the free endthereof is likely to cause the angle between the two arm sections tobecome more obtuse. A counterbalance has heretofore been proposed as.anexpedient to counteract the weight of the arm.

While the vertical and horizontal lines on a drawing may beperpendicular to one another, it is sometimes found, where changes areto be made to the drawing and it is again ailixed to a drawing board forthat purpose, that such vertical and horizontal lines are each at aslight and equal angle to the respective vertical and horizontalstraight-edges carried by the drafting machine to be used by thedraftsman about to make changes on or additions to the drawing. Shiftingthe drawing on the drafting table so that the base line thereofcoincides with the straight-edge about to be used is not alwayspractical.

One object of the present invention is to provide a drafting machinewhereof the straightedges may be adjusted to conform to the linesalready drawn. Such an adjustment is commonly referred to as a base lineadjustment. In carrying this aspect of the invention into effect, theinstrumentalities maintaining the straight-edges in orientation, in thisinstance, an endless belt and pulley, are capable of being angularlyshifted to that degree necessary to cause a straight-edge to coincidewith a given base line.

It is also an object of the invention to enable a draftsman to work fromany base line from horizontal to vertical up or vertical down or fromClaims.

any base line intermediate between these verticals. By this invention,the straight-edges may be so set as to conform to the angularly disposedbase line and the protractor adjusted so that the base line is indicatedat zero on the scale of the protractor.

Another object of the invention is base line adjusting means enablingany degree of adjustment necessary within wide limits. Accordingly, themeans maintaining the straight-edges in orientation are mounted formovement independently of the anchor.

A further object of the invention is a drafting machine anchor in whichthe orientation of the straight-edges may be readily effected by amanipulation at the anchor. To this end, in one aspect of the invention,a freely rotatable anchor pulley is latched in adjusted position to theanchor.

It is also an object of the invention to provide devices which willpermit substantially unlimited adjustment of the base line. In carryingout this aspect of the invention, the anchor pulley is so mounted forrotation as to be rotatable through any desired angle usually more thanand up to substantially 360. This is dependent upon the relation of thesize of the pulley, the length of the arms, and the initial position ofadjustment and/or relative location of the means used to secure and/ordetermine the tension of the endless bands.

Yet another object of the invention is positioning means for the anchorpulley operable at substantially any degree of rotation thereof andwhich is readily manipulated by the draftsman without requiring the useof tools.

Again, it is soughtby this invention to permit maximum adjustment of ananchor pulley and band, while at the same time obviating damage to theband were a turnbuckle or other joining means for the ends of a band toride up on a pulley. To this end, stop means are provided limitingrotation of both the anchor pulley and the drafting machine arm aboutthe anchor, as will be described hereinafter.

The invention also seeks base line adjusting means which are practicalfrom the standpoint of simplicity of manufacture and convenience andaccuracy in use.

These and. other objects of the invention and the means for theirattainment will be more ap parent from the following detaileddescription, taken in connection with the accompanying drawingsillustrating one embodiment by which the invention may be realized andin which;

shown, to insure the banden'gaging the pulley with a driving friction.Since the anchor pulley 3| in the machine as described is rotatable whenthe clamping means is released, it is "desirable to limit such rotationof the pulley so as to prevent damage or breakage of the bands by theturnbuckle riding up on the pulleys. It is desirable therefore, to limitthe rotation of the pulley at least to such extent asto prevent damagingcontact of the means joining the bands and the pulleys, Accordingly, twopins or lugs 60 (Figures 2 and 4) are mounted on the underside of pulley3! so that when the pulley is rotated in either direction relative tothe anchor, one of the lugs {it will engage the boss '6! and therebylimit the movement of the pulley 3i with respect'to the anchor. From theposition of the pulley as illustrated in Figure 4, this rotation wouldbe a little more than ninety degrees in both directions.

It will be observed that the passage portion '53 is normally on theopposite side of the axis of the pulley from the boss BI and spacedapproximately equiangularly from the pins 60. Thus, the clamping plate5'! never traverses the en larged portion 13 of the groove 5l-53 in thenormal operation of the machine.

When the pulley 3| is latched to the anchor, rotation of the arm 23about the anchor might also cause the joining means of the bands to rideup on a pulley in the same manner as the rotation of the unlatchedpulley with respect to the anchor. The combined effect of rotation ofthe pulley 3| about the anchor for adjustment of the straight-edges to adesired base line and rotation of the arm 23 about the anchor in thenormal use of the machine might be cumulative or in opposition dependingupon the direction of the rotation of the pulley for base lineadjustment and the direction of rotation of the arm in the use of themachine, To prevent damage to the machine, it is desirable to limit therotation of the arm 23 about the anchor to some predetermined angle suchas slightly less than 360.

: To this end, in the illustrative embodiment, a

pin or lug 69 is disposed radially on the pivot pin 2! and a stop Mfixed in the anchor at the desired place so that the pin 69 turning ineither direction with the sleeve 21 and pivot pin 2i engages the stop TIand thereby prevents the arm 23 from rotating through more than slightlyless than 360.

It will thus be seen that an anchor is provided for draftingmachines inwhich the proper positioning of the straight-edges is effected by anadjustment self-made, so to speak, by the instrument itself andrequiring only that the pulley be released and the straight-edges beturned to coincide with a base line whereupon the straightedges arelatched in adjusted position by a manipulation at the anchor.

Various modifications will occur to those skilled in the art in thedisposition and configuration of the component elements going to make upthe invention as a whole as well asin the mechanical movements adaptedto effect the adjustment and fixing of the anchoring pulley, and nolimitation is intended by the phraseology of the foregoing descriptionor illustrations in the accompanying drawings except as indicated in theappended claims.

What is claimed is:

1. In a drafting machine of the wheel and band type having an anchor,the combination with a pulley therein about which the band passes inmaintaining the straight edge means in orientation: of means 'mountingsaid pulley for free rotation, said pulley being formed with an annularshoulder, clamping means disposed on the shoulder, and actuating meanscarried by the anchor to actuate said clamping means and causesaidclamping means'to engage on the shoulder and retain the pulley inadjusted position.

2. In a drafting machine ,of the wheel and band type having an anchor,the combination with a pulley therein;- about which the band passes inmaintaining the straight edge means in orientation: of means mountingsaid pulley for-free rotation, said pulley, being formed with an annulargroove having a shoulder, and adjustably mounted means carried by, theanchor and engaging the shoulder to retain the pulley in adjustedposition.

3. In a drafting machine of the wheel and band type having an anchor,the combination with a pulley therein about which the band passes inmaintaining the straight edge means in orientation: of means mountingsaid pulley for free rotation, said pulley being provided with ashoulder and means carried by the anchor and engaging the shoulder toretain the pulley in adjusted position.

4. In a drafting machine of the wheel and band type having an anchor,the combination with a pulley therein about which the band passes inmaintaining the straight edge means in orientation: of means mountingsaid pulley for free rotation, said pulley being formed with an arcuategroove concentric with the axis of the pulley and T-shaped incross-section and clamping means T-shaped in cross-section carried bythe anchor and disposed in the groove to retain the pulley in adjustedposition.

5. In a drafting machine of the wheel and band type having an anchor,the combination with an arcuately movably mounted member therein aboutwhich the band passes in maintaining the straight edge means inorientation: of the arcuately movably mounted member provided with anarcuate slot, clamping means carried by the anchor means and passingthrough the slot and engaging the arcuately movably mounted member, andmanually actuatable lever means to draw said clamping means intoclamping engagement with said arcuately movably mounted member to retainsaid arcuately movably mounted member in adjusted position.

6. In a drafting machine of the wheel and band type having an anchor,the combination with an arcuately movably mounted member therein aboutwhich the band passes in maintaining the straight edge means inorientation: of said arcuately movably mounted member provided with anarcuate slot, clamping means carried by the anchor means comprising ahelically grooved shaft disposed in the slot in the arcuately movablymounted member, a clamping plate on the shaft, sleeve means on the shaftand coacting lever means to draw the plate into clamping engagement withthe arcuately movably mounted member and retain said member in adjustedposition.

'7. In a drafting machine of the wheel and band type having an anchor,the combination with a pulley therein about which the band passes inmaintaining the straight edge means in orientation: of manipulatorymeans carried by the anchor and engaging the pulley at a selected one ofa plurality of positions to maintain said lastnamed means in adjustedposition and means to limit the movement of the pulley comprising a stopon time anchor and: a meeting step out the tion: of at least one armpivotaily mounted on said author, an annular passage in the pulleyhaving a surface, means in the passage carried by the anchor and adaptedto engage the surface to retain the pulley in adiusted position, said 8V band type having an anchor, the combination with a pulleytherein-about which the band passes in maintaining the" straight edgemeansin orien-i tation: of an amulet passage in the pulley having a,surface, means in the passage carriedby the anchor and adapted toengagethe surface to anchor also oomp'risirig stop means limiting reIa- 20tive rotation of the arm; 7 7

'10. in a drafting machine of the wheel and retain the pulley inadjusted position, said anchor also comprising stop means and a lug onsaid pulley engageable by the stop means and limitir g rotation of thepulley in either direction LEENDERT KETTING REFERENCES CITED Thefollowing references areof record in the flie' of this patent: 7 r VUNITED STATES PATENTS Number Name Date 2,137,604 Lah'gsner w n ed; Nov;15; 1938 2 2,289,126 Keufiel 'Juiy 7,- 1942 2,316,485 Lengsner 422-52--Apr. 13,1943 2,332,860

